Optimal low-thrust interception and deflection of Earth-crossing asteroids

The spectacular collision of the Shoemaker-Levy 9 asteroid with Jupiter in July 1994 was a dramatic reminder of the inevitability of such catastrophes in the Earth's future unless steps are taken to develop methods for Earth-approaching object detection and possible interdiction. In this work optimal (minimum-time) very-low-thrust trajectories using electric propulsion are determined for the interception of asteroids which pose a threat of collision with the Earth. At the time of interception the system state transition matrix is found and used to indicate the direction in which an impulse should be applied to the asteroid to maximize the subsequent deflection.